Zoltan2_StridedData.hpp

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//   Zoltan2: A package of combinatorial algorithms for scientific computing
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#ifndef _ZOLTAN2_STRIDEDDATA_HPP_
#define _ZOLTAN2_STRIDEDDATA_HPP_

#include <Zoltan2_Standards.hpp>
#include <Zoltan2_Environment.hpp>
#include <typeinfo>

namespace Zoltan2{

template<typename lno_t, typename scalar_t>
class StridedData {
private:
  ArrayRCP<const scalar_t> vec_;
  int stride_;

public:

  StridedData(ArrayRCP<const scalar_t> x, int stride) :  
    vec_(x), stride_(stride) { }

  StridedData(): vec_(), stride_(0) { }

  lno_t size() const { return vec_.size(); }

  scalar_t operator[](lno_t idx) const { return vec_[idx*stride_]; }

  template <typename T> void getInputArray(ArrayRCP<const T> &array) const;

  void getStridedList(ArrayRCP<const scalar_t> &vec, int &stride) const
  {
    vec = vec_;
    stride = stride_;
  }

  void getStridedList(size_t &len, const scalar_t *&vec, int &stride) const
  {
    len = vec_.size();
    vec = vec_.getRawPtr();
    stride = stride_;
  }

  StridedData & operator= (const StridedData &sInput)
  {
    if (this != &sInput)
      sInput.getStridedList(vec_, stride_);

    return *this;
  }
};

template<typename lno_t, typename scalar_t>
  template<typename T>
     void StridedData<lno_t, scalar_t>::getInputArray(
       ArrayRCP<const T> &array) const
{
  if (vec_.size() < 1){
    array = ArrayRCP<const T>();
  }
  else if (stride_==1 && typeid(T()) == typeid(scalar_t())){
    array = vec_;
  }
  else{
    Environment env;           // a default environment for error reporting
    size_t n = vec_.size() / stride_;
    T *tmp = new T [n];
    env.localMemoryAssertion(__FILE__, __LINE__, n, tmp);
    for (size_t i=0,j=0; i < n; i++,j+=stride_){
      tmp[i] = static_cast<T>(vec_[j]);
    }
    array = arcp(tmp, 0, n);
  }
  
  return;
}

}  // namespace Zoltan2

#endif